“There Is no bad weather, just different kinds of good weather.” – Anonymous

It all depends on your perspective, but many Minnesotans may find near weather perfection over the next 2 weeks.

If you like sunny mild days and cool nights with “good sleeping weather” this forecast is for you. The only weather complaint you may be able to muster is asking for a little water for your lawn, garden or farm field.

More good news? The 2013 tornado drought continues. The atmosphere over Minnesota has mustered only 6 tornadoes so far in 2013. That’s good news by anyone’s measure. I have yet to hear a compelling case for tornadoes as “good weather,” but I suppose it can be money in the bank if you’re a storm chaser grabbing the money shot to sell to TV news?

Our dry northwest flow means nearly perfect weather the next few days. High near 80 in the Twin Cities metro area, and 70s up north will be the rule. Overnight lows will be in the coolish 50s with big daily “diurnal variations” — big swings from morning low to afternoon highs of about 30 degrees thanks to dry air overhead.

Here’s an interesting development. NOAA may experiment with seasonal toandos outlooks by next summer. The outlooks could be similar to hurricane forecasts. Time will tell if they are accurate or valuable. Details from Bob Henson at UCAR News.

July 30, 2013 | Just as forecasters now peg the odds of a busy Atlantic hurricane season months in advance, we might soon have outlooks that assess the risk of an active tornado season weeks or even months ahead of time.

Such a system isn’t yet on the drawing board, but researchers are exploring how it might work. A white paper prepared earlier this year by a team of NOAA and university scientists is now making the rounds, and a testbed could be in place as soon as the spring of 2014.

“We’d like to move toward something probabilistic, much like the hurricane outlooks,” says NOAA’s Scott Weaver. He’s the lead author of the white paper, which includes the testbed idea as well as a variety of other recommendations.

The white paper emerged from workshops in May 2012 and March 2013 (see writeup and video clips here) that included tornado specialists, climate scientists, and representatives from the insurance industry.

“We’re interested in learning the best ways to make this useful to decision makers,” says Weaver.

Scientific underpinnings

The push to explore extended (two- to six-week) and seasonal (three-month) tornado prediction has gained momentum due to several factors.

Researchers are understanding more clearly how multiyear cycles such as El Niño and La Niña and the Pacific Decadal Oscillation influence tornado frequency. For example, when La Niña is transitioning to El Niño during springtime, the odds of a major tornado outbreak—especially in the Midwest and South—appear to be almost twice as large as in neutral springs, according to a recent Journal of Climate paper led by Sang-Ki Lee (University of Miami/NOAA).

The NOAA Climate Forecast System (CFS) now issues nine-month forecasts of U.S. circulation anomalies four times each day. This makes it a potential foundation for building weekly to seasonal tornado outlooks.

High-resolution regional models that simulate thunderstorms directly—such as ARW, the NCAR-based Advanced Research Weather Research and Forecasting Model—can now be linked to larger-scale climate models. This helps provide clues to how coarser-resolution climate models, which can be run more affordably for larger regions and longer time periods, might be used to estimate tornado frequency. Jeff Trapp (Purdue University) and colleagues have found some success in reproducing past severe weather events through this strategy.

About the blogger

Paul Huttner is chief meteorologist for Minnesota Public Radio. Huttner has worked TV and radio stations in Minneapolis, Tucson and Chicago. Paul is a graduate of Macalester College in St. Paul and holds a bachelor’s degree in geography with an emphasis in meteorology.